JP2021060071A - Tapered roller bearing - Google Patents

Abstract

To provide a tapered roller bearing capable of; preventing seizure even under lubrication circumstances where lubricating oil is intermittently supplied or the lubricating oil is in trace amounts; holding the lubricating oil in oil holding holes for a long time even when applied with centrifugal force generated by the rotation of the bearing; holding the lubricating oil in the oil holding holes for a long time even during bearing standstill; and achieving stable oil supply to rollers.SOLUTION: In a large-diameter side annular part 15 of a cage 14, oil holding holes 20 for holding lubricating oil with capillary force are formed passing through the large-diameter side annular part 15 in an axial direction. A radial width W of the oil holding hole 20 is 0.5 mm or smaller and configured to become gradually smaller as extending from an axial outer side to an axial inner side. A face 21 on a most outer diameter side of the oil holding hole 20 is formed substantially parallel to a bearing center axis CL.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tapered roller bearing, and more particularly to a tapered roller bearing in which lubricating oil is supplied to the inside of the bearing.

In recent years, a mechanism for stopping the lubricating oil pump when the engine is stopped, such as the transmission of some hybrid vehicles, has appeared, which tends to cause a seizure problem of bearings. In addition, when the vehicle is towed, the lubricating oil pump does not operate and the tires spin, which may cause seizure of the bearings in the transmission. Therefore, there is a demand for bearings that can prevent seizure even in a lubricating environment in which the supply of lubricating oil is intermittent or in a lubricating environment in which a small amount of lubricating oil is used.

As a conventional tapered roller bearing, the outer ring, the inner ring, a plurality of tapered rollers incorporated between the outer ring and the inner ring, and an annular cage for maintaining the circumferential distance between the plurality of tapered rollers are provided and held. It is known that an oil-retaining hole is formed in the large-diameter annular portion of the vessel by opening the large-diameter pocket surface to introduce and hold the lubricating oil by capillarity (see, for example, Patent Document 1). ).

JP-A-2018-159411

By the way, in the tapered roller bearing described in Patent Document 1, the hole diameter of the oil-retaining hole is set so as to gradually increase from the outer side in the axial direction toward the inner side (roller side) in the axial direction, and the outermost diameter of the oil-retaining hole is set. The side surface is formed so as to gradually incline outward in the radial direction toward the inside in the axial direction. Further, the pore diameter of the oil retention hole is also set to 2 mm or less (preferably 1.5 mm or less), and the oil retention hole is too large to hold the lubricating oil by capillary force. For these reasons, the lubricating oil flows out from the oil retention holes in a short time due to the centrifugal force accompanying the rotation of the bearing. Therefore, the lubricating oil can be held from the stationary state of the bearing to immediately after the start of rotation, and the bearing rotates. In the state, the lubricating oil could not be held in the oil retention holes for a long time. Further, since the pore diameter of the oil retention hole is large and the capillary force is low, the lubricating oil cannot be retained in the oil retention hole for a long time even when the bearing is stationary. Furthermore, since the pore diameter of the oil retention hole is set to gradually increase from the outside in the axial direction toward the inside (roller side) in the axial direction, the capillary force acts strongly in the direction of separating the lubricating oil from the rollers, so that the capillary force is increased. It was difficult to provide stable refueling by using it.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to burn even in a lubricating environment in which the supply of lubricating oil is intermittent or in a lubricating environment in which a small amount of lubricating oil is used. It is possible to prevent sticking, and even if centrifugal force due to bearing rotation acts, the lubricating oil can be retained in the oil retention holes for a long time, and the lubricating oil can be retained in the oil retention holes for a long time even when the bearing is stationary. It is an object of the present invention to provide tapered roller bearings that can be held and that can stably lubricate rollers.

The above object of the present invention is achieved by the following configuration.
(1) An outer ring having an outer ring raceway surface on the inner peripheral surface, an inner ring having an inner ring raceway surface on the outer peripheral surface, and a plurality of tapered rollers provided so as to be rollable between the outer ring raceway surface and the inner ring raceway surface. A cage that holds the plurality of tapered rollers at substantially equal intervals in the circumferential direction is provided, and the cage has a large diameter side annular portion and a small diameter arranged coaxially with the large diameter side annular portion. The side annular portion, the large-diameter side annular portion, and the small-diameter side annular portion are connected in the axial direction, and a plurality of pillar portions provided at substantially equal intervals in the circumferential direction are adjacent to each other in the circumferential direction. A tapered roller bearing having a pocket formed between columns and holding the tapered roller so that it can roll, and at least one tapered roller bearing having a large diameter side annular portion holding lubricating oil by capillary force. The oil-retaining hole is formed so as to penetrate the large-diameter annular portion in the axial direction, and the radial width of the oil-retaining hole is 0.5 mm or less and gradually decreases from the outer side in the axial direction to the inner side in the axial direction. Tapered roller bearings, characterized in that the outermost diameter side surface of the oil retaining holes is formed substantially parallel to the bearing central axis.
(2) The tapered roller bearing according to (1), wherein the innermost surface of the oil retention hole is formed so as to gradually incline outward in the radial direction toward the inner side in the axial direction.
(3) The tapered roller bearing according to (1) or (2), wherein the oil retaining hole has a circular shape or a slit shape along the circumferential direction of the large diameter side annular portion.
(4) The large-diameter side end face of the tapered roller is provided around the circular recess formed in the center of the large-diameter end face and the recess, and is within the axial direction of the large-diameter annular portion. It has an annular contact surface that can contact the end surface, and the opening of the oil retention hole on the tapered roller side is such that the annular contact surface and the axial inner end surface of the large diameter side annular portion are formed. The tapered roller bearing according to any one of (1) to (3), wherein the tapered roller bearing is provided so as to fit in an overlapping region in the longitudinal direction of the tapered rollers.
(5) The tapered roller bearing according to any one of (1) to (4), wherein the inner end surface of the large-diameter annular portion in the axial direction is formed in a concave spherical shape.
(6) Any one of (1) to (5), wherein the lubricating oil is intermittently supplied to the inside of the bearing, or the lubricating oil inside the bearing is used in a lubricating environment in a small amount. Tapered roller bearings listed in 1.

According to the present invention, at least one oil-retaining hole for holding the lubricating oil by the capillary force is formed in the large-diameter annulus portion of the cage so as to penetrate the large-diameter annulus portion in the axial direction. Even if the amount of lubricating oil in the bearing is small without supplying the lubricating oil to the bearing, the lubricating oil stored in the oil retention holes is supplied to the large-diameter side end face of the cone. Therefore, seizure of the bearing can be prevented even in a lubricating environment in which the supply of the lubricating oil is intermittent or in a lubricating environment in which the amount of the lubricating oil is very small.

Further, since the radial width of the oil retention hole is set to 0.5 mm or less to obtain a strong capillary force, the lubricating oil can be held for a long time only by the oil retention hole when the bearing is stationary. In addition, since the outermost surface of the oil retention hole is formed substantially parallel to the bearing center axis, the influence of centrifugal force due to the bearing rotation acting on the lubricating oil in the oil retention hole is minimized, and the bearing rotation. Lubricating oil can be retained in the oil retention holes for a long time even if the centrifugal force associated with the above acts. Further, since the radial width of the oil retention hole is set to gradually decrease from the outside in the axial direction to the inside in the axial direction, the capillary force acts in the direction of approaching the lubricating oil to the tapered roller, and the oil retention hole is formed. Stable refueling can be performed when it comes into contact with the large-diameter side end face of tapered rollers.

It is sectional drawing explaining one Embodiment of the tapered roller bearing which concerns on this invention. It is an enlarged cross-sectional view around the large-diameter side ring portion shown in FIG. It is a schematic diagram which shows the positional relationship between the oil retention hole in the cage shown in FIG. 1 and the large diameter side end face of a tapered roller. It is a schematic diagram explaining the 1st modification of a cage. It is a schematic diagram explaining the 2nd modification of a cage. It is a schematic diagram explaining the 3rd modification of a cage. It is a schematic diagram explaining the 4th modification of a cage. It is a schematic diagram explaining the 5th modification of a cage. It is sectional drawing explaining the lubrication to a bearing by a lubricating oil pump. It is sectional drawing explaining the lubrication to a bearing by the bouncing of a gear.

Hereinafter, an embodiment of a tapered roller bearing according to the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the tapered roller bearing 10 of the present embodiment has an outer ring 11 having an outer ring raceway surface 11a on the inner peripheral surface, an inner ring 12 having an inner ring raceway surface 12a on the outer peripheral surface, and an outer ring raceway surface 11a and an inner ring. A plurality of tapered rollers 13 provided so as to be rollable between the raceway surface 12a and a cage 14 for holding the plurality of tapered rollers 13 at substantially equal intervals in the circumferential direction are provided. In the present embodiment, the lubricating oil circulating inside the housing H (see FIG. 9) is appropriately supplied to the inside of the bearing by the lubricating oil pump P (see FIG. 9) or the like.

The inner ring 12 has a large collar portion 12b provided at the large diameter side end portion of the inner ring 12 and a small collar portion 12c provided at the small diameter side end portion of the inner ring 12. The inner ring raceway surface 12a of the inner ring 12 is formed in a substantially conical shape. Further, the inner peripheral surface (outer ring raceway surface 11a) of the outer ring 11 is formed in a substantially conical shape.

The tapered roller 13 is provided on a rolling surface 13a provided on the peripheral surface of the tapered roller 13, a large-diameter side end surface 13b provided on the large-diameter side end of the tapered roller 13, and a small-diameter side end of the tapered roller 13. It has a small diameter side end surface 13c. Further, the large-diameter side end surface 13b is formed in a convex spherical shape having a radius of curvature Ra, and a circular recess 13d is formed in the central portion thereof. The center of the convex spherical surface is located on the rotation axis of the tapered roller 13.

The cage 14 is made of synthetic resin and is injection-molded by an axial draw. As shown in FIGS. 1 to 3, the cage 14 is coaxially arranged with the large-diameter annulus portion 15 and the large-diameter annulus portion 15. The small-diameter ring portion 16 and the large-diameter ring portion 15 and the small-diameter ring portion 16 are connected in the axial direction, and a plurality of pillar portions 17 provided at substantially equal intervals in the circumferential direction are connected in the circumferential direction. It has a pocket 18 formed by being surrounded by a large-diameter annulus portion 15 and a small-diameter annulus portion 16 between pillar portions 17 adjacent to each other and holding a conical roller 13 so as to be rollable.

Further, the cage 14 has a first gap S1 having a roller axial dimension of D1 between the axial inner end surface 16a of the small diameter side annular portion 16 of the cage 14 and the small diameter side end surface 13c of the tapered roller 13. Have. Further, the cage 14 has a second gap in which the roller axial dimension between the axial inner end surface 15a of the large diameter side annular portion 15 of the cage 14 and the large diameter side end surface 13b of the tapered roller 13 is D2. It has S2. The roller axis direction dimensions D1 and D2 are dimensions along the central axis (rotation axis) direction of the tapered roller 13.

Further, the surface of the axial inner end surface (hereinafter, also simply referred to as “pocket surface”) 15a of the large diameter side annular portion 15 of the cage 14 is roughly formed, and the specific surface roughness of the pocket surface 15a is formed. (Arithmetic mean roughness) is set to 3 μm to 20 μm.

The roughness of the pocket surface 15a of the large-diameter annular portion 15 functions to guide the lubricating oil stored in the oil-retaining holes 20 described later to the tapered rollers 13. Thereby, the oil retention capacity and the oil supply capacity of the pocket surface 15a can be enhanced. Further, it is preferable that the inner surface of the oil retention hole 20 described later is also roughly formed in order to enhance the oil retention capacity. Further, since the pocket surface 15a is substantially perpendicular to the die-cutting direction during molding of the cage, even if the pocket surface 15a is roughly formed, it does not hinder the mold release after molding. The surface roughness of the pocket surface 15a may be set for all pockets 18 or for some pockets 18.

The pocket surface 15a of the large diameter side annular portion 15 is formed in a concave spherical shape having a radius of curvature SRy. The concave spherical radius of curvature SRy of the pocket surface 15a is set within ± 10% of the convex spherical radius of curvature Ra of the large diameter side end surface 13b of the cone 13 (0.9Ra ≦ SRy ≦ 1). .1Ra). As a result, the degree of adhesion between the pocket surface 15a and the large diameter side end surface 13b of the tapered roller 13 is improved, so that a high oil retention and refueling effect can be obtained. However, if SRy is matched with Ra (SRy = Ra) and hits the entire surface, the frictional resistance increases. Therefore, the optimum state is that the radius of curvature is slightly shifted so that the SRy is not completely adhered.

Further, as shown in FIGS. 1 to 3, three oil retention holes 20 for holding the lubricating oil by capillary force are formed in the large diameter side annular portion 15 of the cage 14. The oil retention hole 20 has a partially conical shape (the cross-sectional shape in a plane orthogonal to the bearing center axis CL is substantially circular), and is formed so as to penetrate the large diameter side annular portion 15 in the axial direction. The oil retention hole 20 opens in a substantially circular shape on the pocket surface 15a. The oil retention holes 20 may be provided in all the pockets 18 or in some pockets 18. Further, one or more oil retention holes 20 may be formed, and the number thereof is arbitrary. Further, the cross-sectional shape of the oil retention hole 20 is not limited to a circular shape, and can be changed to an arbitrary shape such as a polygonal shape such as a triangle shape or a rectangular shape, a star shape, or a teardrop shape (drop shape).

Further, the radial width (hole diameter) W of the oil retention hole 20 is set to be 0.5 mm or less and gradually decrease from the outer side in the axial direction to the inner side in the axial direction. Specifically, in the present embodiment, the radial width (hole diameter) W1 of the axial outer end of the oil retention hole 20 is 0.5 mm, and the radial width (hole diameter) W2 of the axial inner end of the oil retention hole 20 is 0. It is set to 2 mm. Further, the outermost surface 21 of the oil retention hole 20 is formed substantially parallel to the bearing central axis CL. Further, the surface 22 on the innermost inner diameter side of the oil retention hole 20 is formed so as to gradually incline outward in the radial direction toward the inner side in the axial direction.

In the tapered roller bearing 10 configured in this way, lubricating oil is supplied to the large-diameter side end surface 13b of the tapered roller 13 by capillarity only when the oil-retaining hole 20 and the large-diameter side end surface 13b of the tapered roller 13 come into contact with each other. Lubrication. Further, when not in contact, the lubricating oil is held in the oil retention holes 20 by the capillary force, so that the lubricating oil does not flow out from the oil retention holes 20.

FIG. 3 is a schematic view showing the positional relationship between the oil retention hole 20 and the large diameter side end surface 13b of the tapered roller 13. The large-diameter side end surface 13b of the tapered roller 13 has a circular recess 13d formed in the center of the large-diameter side end surface 13b and an annular contact surface provided around the recess 13d and capable of contacting the pocket surface 15a. It has 13e and. The openings on the tapered roller 13 side of the three oil retention holes 20 are regions where the large diameter side end surface 13b of the tapered roller 13 and the pocket surface 15a overlap in the longitudinal direction of the tapered roller 13 (viewed in the longitudinal direction of the tapered roller 13). It is provided so that it fits in the overlapping area). More specifically, among the three oil retention holes 20, the oil retention hole 20 located at the center in the circumferential direction has a conical contact surface 13e and a pocket surface 15a in the entire opening on the tapered roller 13 side. The rollers 13 are provided so as to fit in the overlapping regions in the longitudinal direction. On the other hand, of the three oil retention holes 20, the two oil retention holes 20 located on both sides in the circumferential direction have an annular contact surface in which only a part of the opening on the tapered roller 13 side (approximately half in the illustrated example) is formed. The 13e and the pocket surface 15a are provided so as to fit in the overlapping region of the tapered roller 13 in the longitudinal direction. As described above, in the case of the present embodiment, the opening of the oil retention hole 20 on the tapered roller 13 side has at least a part of the opening end in the longitudinal direction of the tapered roller 13 in which the annular contact surface 13e and the pocket surface 15a are in the annular direction. It is provided so as to fit in the overlapping area.

The cage 14 is made of synthetic resin and can be injection molded by, for example, an axial draw. The surface roughness of the pocket surface 15a of the large diameter side annular portion 15 and the oil retention hole 20 can also be formed at the same time by this injection molding. In this case, it is not necessary to add a processing process, special molding such as two-color molding (double molding), and bonding of a separately manufactured oil-retaining member. Therefore, the seizure resistance can be improved without increasing the manufacturing cost.

The material of the cage 14 is not particularly limited, and examples thereof include a general cage resin material such as nylon. The synthetic resin of the cage 14 may contain fibers as a reinforcing agent.

In the tapered roller bearing 10 configured in this way, when lubricating oil is supplied to the bearing and the inside of the bearing is filled with the lubricating oil, the lubricating oil is transferred from the small diameter side to the large diameter side of the inner ring 12 by the pumping action of the bearing rotation. A flowing phenomenon occurs. Therefore, the cage 14 moves in the axial direction toward the large diameter side of the tapered roller 13 under the force of the flow of the lubricating oil due to the pumping action, so that the large diameter side annular portion 15 of the cage 14 is the tapered roller 13. The oil-retaining hole 20 of the large-diameter annular portion 15 and the large-diameter end surface 13b of the tapered roller 13 are not in contact with each other. At this time, the lubricating oil supplied to the bearing is stored in the oil retention hole 20 by the capillary force.

On the other hand, when the lubricating oil is not supplied to the bearing and the amount of the lubricating oil in the bearing is small, the flow of the lubricating oil does not occur due to the pumping action, and the cage 14 moves to the small diameter side of the tapered rollers 13 due to the component force of its own weight. Since it moves in the axial direction, the oil-retaining hole 20 of the large-diameter side annular portion 15 of the cage 14 comes into contact with the large-diameter side end surface 13b of the tapered roller 13. As a result, the lubricating oil stored in the oil retention hole 20 is supplied to the large diameter side end surface 13b of the tapered roller 13. That is, only when the amount of lubricating oil in the bearing is very small, the oil-retaining hole 20 comes into contact with the large-diameter side end surface 13b of the tapered roller 13, and the lubricating oil is supplied to the tapered roller 13. Since the tapered roller bearing 10 of the present invention moves the cage 14 by utilizing the component force of the weight of the cage 14, it is used in a structure that supports a horizontally provided shaft (horizontal shaft). Is preferable.

As described above, according to the tapered roller bearing 10 of the present embodiment, the large-diameter side annular portion 15 of the cage 14 has three oil-retaining holes 20 for holding the lubricating oil by capillary force. Since it is formed so as to penetrate the ring portion 15 in the axial direction, even if the lubricating oil is not supplied to the bearing 10 and the amount of the lubricating oil in the bearing 10 becomes very small, the lubricating oil stored in the oil retention hole 20 is tapered. It is supplied to the large-diameter side end surface 13b of the roller 13. Therefore, seizure of the bearing 10 can be prevented even in a lubricating environment in which the supply of lubricating oil is intermittent or in a lubricating environment in which a small amount of lubricating oil is used.

Further, since the radial width W of the oil retention hole 20 is set to 0.5 mm or less to obtain a strong capillary force, the lubricating oil can be held for a long time only by the oil retention hole 20 when the bearing is stationary. Further, since the outermost surface 21 of the oil retention hole 20 is formed substantially parallel to the bearing central axis CL, the influence of the centrifugal force due to the rotation of the bearing acting on the lubricating oil in the oil retention hole 20 is minimized. Even if the centrifugal force due to the rotation of the bearing acts, the lubricating oil can be held in the oil retention hole 20 for a long time. Further, since the radial width W of the oil retention hole 20 is set to gradually decrease from the outer side in the axial direction to the inner side in the axial direction, the capillary force acts in the direction of bringing the lubricating oil closer to the tapered roller 13 and retains the oil. Stable lubrication can be performed when the oil hole 20 comes into contact with the large-diameter side end surface 13b of the tapered roller 13.

Further, according to the tapered roller bearing 10 of the present embodiment, the amount of lubricating oil can be significantly reduced, so that the stirring resistance of the lubricating oil can be reduced. Further, for example, if the structure is such that even a small amount of lubricating oil can be supplied by splashing with gears (see FIG. 10), the lubricating oil pump and the oil supply passage can be eliminated, thereby making the entire lubrication system lightweight and compact. , Cost reduction can be achieved.

Further, according to the tapered roller bearing 10 of the present embodiment, the bearing is prevented from seizure even in a lubricating environment where lubricating oil is intermittently supplied into the bearing or the amount of lubricating oil in the bearing is very small. Performance and lubrication effect can be maintained for a long period of time. Therefore, the tapered roller bearing 10 of the present embodiment can be suitably used for a mechanism such as a transmission of some hybrid vehicles in which the lubricating oil pump is temporarily stopped when the engine is stopped, and also for an automobile. It is possible to deal with situations where it is difficult to supply sufficient lubricating oil because the lubricating oil pump does not operate when the vehicle is towed.

Here, a lubrication environment in which the amount of lubricating oil in the present specification is very small will be described. For example, in the case of a transmission such as an automobile, there are generally two methods of supplying lubricating oil: pumping the lubricating oil by the lubricating oil pump P shown in FIG. 9 and splashing the lubricating oil by the gear G shown in FIG. Known for.

As a structure for pumping lubricating oil by the lubricating oil pump P, as shown in FIG. 9, the outer ring 11 of the tapered roller bearing 10 is fitted inside the housing H, and the inner ring 12 is fitted outside the rotating shaft A, and the housing. A structure is generally known in which a lubrication passage R communicating with the bearing 10 is provided in H, and a lubricating oil pump P is connected to the lubrication passage R. In the case of this structure, the lubricating oil pumped from the lubricating oil pump P is supplied to the bearing 10 via the oil supply passage R.

Further, as a structure in which the lubricating oil is splashed by the gear G, as shown in FIG. 10, the outer ring 11 of the tapered roller bearing 10 is fitted inside the housing H, and the inner ring 12 is fitted outside the rotating shaft A to rotate. A structure in which a gear G is provided on the shaft A adjacent to the inner ring 12 is generally known. In the case of this structure, the lubricating oil adhering to the gear G scatters due to the centrifugal force accompanying the rotation of the shaft, and the scattered lubricating oil adheres to the bearing 10 and is supplied.

In the above two types of structures, an amount of lubricating oil of about 50 cc / min to 1000 cc / min is supplied in order to prevent seizure of the bearing. If the amount of the lubricating oil is less than 10 cc / min, heat generation and seizure are likely to occur due to the lack of oil film due to the shortage of the lubricating oil, and seizure occurs at 0 cc / min (non-lubricated oil). The present invention corresponds to a dilute lubricated state rather than a non-lubricated state, and has a great effect in a lubricating environment where a small amount of lubricating oil is used, specifically, in a dilute lubricated state of about 0.01 cc / min to 10 cc / min. Demonstrate.

Next, the environment in which the lubricating oil is intermittently supplied in the present specification will be described. For example, in a hybrid vehicle, there is a mode in which the vehicle runs on an electric motor with the engine stopped. In this mode, in the structure of only the lubricating oil pump directly connected to the engine, running is performed in a state where the lubricating oil is not supplied to the bearings. For this reason, a non-lubricated running state occurs for up to several minutes, but the bearing must not seize during this period. There is a need to extend this electric running time with the evolution of batteries. At present, in order to prevent seizure, there are some models that control the operation of the lubricating oil pump by rotating the engine at regular intervals. To solve this problem, it is necessary to add an electric lubricating oil pump to the system or to adopt a non-lubricating and seizure-resistant bearing as in the present invention. In the present invention, since the time until seizure is related to the amount of lubricating oil stored in the oil retention holes, the non-lubricating application time can be significantly extended from several tens of minutes to several hours by increasing the amount of lubricating oil. Is possible. The increase in the amount of lubricating oil can be dealt with, for example, by increasing the number of oil retention holes or increasing the area of the oil retention holes.

In addition, a passenger car may be towed as an auxiliary vehicle in the event of a breakdown or at a destination of a large vehicle such as a camper. In such a case, it is possible to prevent idling by mounting the drive wheels of the vehicle on a trolley or the like, but in reality, there are cases where the drive wheels are towed while idling. In this case, there is no drive transmission and the bearing is lightly loaded because of no-load idling. However, in the case of tapered roller bearings, preload is generally applied and the load for the preload is always applied. In this idling state, the engine and the electric lubricating oil pump do not operate, and the lubricating oil pump is stopped, so that the bearings are liable to seize. As a countermeasure for this, some models have devised a drive device so that splash refueling occurs. In the present invention, even if the lubricating oil pump is stopped, the bearings can be refueled until the lubricating oil stored in the oil holding holes is exhausted. The sex can be greatly improved.

In addition, when starting in an extremely cold environment, the lubricating oil freezes, and a phenomenon occurs in which neither lubrication by the lubricating oil pump nor refueling by splashing occurs temporarily. In this case, the lubrication must be covered by a small amount of oil adhering to the bearing itself until the frozen lubricating oil warms and melts. Further, in the present invention, since the frozen lubricating oil is stored in the oil retention holes, the lubricating oil is lubricated while gradually melting as the bearing generates heat, so that the seizure resistance can be dramatically improved.

Next, a first modification of the present embodiment will be described with reference to FIG. In this modification, in the large-diameter ring portion 15 of the cage 14, instead of the circular oil-retaining hole 20, a slit-shaped oil-retaining hole 30 along the circumferential direction of the large-diameter ring portion 15 is provided. It is formed. The oil retention hole 30 is formed so as to penetrate the large diameter side annular portion 15 in the axial direction. Further, the pair of end connecting sides 31 which are both ends in the longitudinal direction of the slit-shaped oil retention hole 30 are formed in a substantially semicircular shape. According to this modification, since the oil retention hole 30 is formed in a slit shape along the circumferential direction of the large diameter side annular portion 15, the amount of lubricating oil stored in the oil retention hole 30 can be increased.

According to this modification, since the radial width of the oil retention hole 30 is set to 0.5 mm or less to obtain a strong capillary force, the lubricating oil is held only in the oil retention hole 30 for a long time when the bearing is stationary. Can be done. Further, since the outer diameter side surface of the oil retention hole 30 is formed substantially parallel to the bearing central axis, the influence of centrifugal force due to the rotation of the bearing acting on the lubricating oil in the oil retention hole 30 is minimized, and the bearing Lubricating oil can be held in the oil retention hole 30 for a long time even if the centrifugal force accompanying the rotation acts. Further, since the radial width of the oil retention hole 30 is set to gradually decrease from the outer side in the axial direction to the inner side in the axial direction, the capillary force acts in the direction of bringing the lubricating oil closer to the tapered rollers 13 to retain the oil. Stable lubrication can be performed when the hole 30 comes into contact with the large-diameter side end surface 13b of the tapered roller 13. The cross-sectional shape of the oil retention hole 30 is the same as that of the oil retention hole 20 shown in FIG.

Further, the oil retention hole 30 is provided so as to fit in a region where the annular contact surface 13e and the pocket surface 15a overlap in the longitudinal direction of the tapered roller 13. As a result, the groove end portion 30a, which is the end portion in the longitudinal direction of the oil retention hole 30, is arranged at a position where it comes into contact with the large diameter side end surface 13b of the tapered roller 13, so that the lubricating oil collected in the groove end portion 30a is collected at the groove end portion. It is possible to efficiently supply the tapered roller 13 from 30a to the large-diameter side end surface 13b.

Next, a second modification of the present embodiment will be described with reference to FIG. In this modification, the pair of end connecting sides 31 of the oil retention holes 30 in the first modification are inclined so that the distance between the pair of ends of the oil retention holes 30 increases in the circumferential direction toward the outside of the large diameter side annular portion 15 in the radial direction. Is formed. In this case, since the groove end portion 30a of the oil retention hole 30 is formed at an acute angle, the capillary force generated at the groove end portion 30a can be increased.

Next, a third modification of the present embodiment will be described with reference to FIG. In this modification, the slit-shaped oil retention hole 30 in the first modification is divided into two in the circumferential direction. According to this modification, the strength of the cage 14 can be increased. The number of divisions of the oil retention holes 30 is arbitrary. Further, in this modification, the entire area of the oil retention hole 30 does not need to come into contact with the large diameter side end surface 13b of the tapered roller 13, and at least one of the two groove end portions 30a comes into contact with the large diameter side end surface 13b. do it. This is because the capillary force of the groove end portion 30a is the highest among the openings of the oil retention hole 30, and if the groove end portion 30a is in contact with the large diameter side end surface 13b (annular contact surface 13e) of the tapered roller 13. This is because refueling can be performed. Further, since the radial width of the oil retention hole 30 is set to 0.5 mm or less and the oil retention hole 30 alone has sufficient oil retention, the opening of the oil retention hole 30 is formed on the large diameter side of the tapered roller 13. Even if the end face 13b is not blocked, the tapered roller 13 can be stably refueled for a long period of time.

Next, a fourth modification of the present embodiment will be described with reference to FIG. 7. In this modification, the slit-shaped oil retention hole 30 in the second modification is divided into two in the circumferential direction. According to this modification, the strength of the cage 14 can be increased. The number of divisions of the oil retention holes 30 is arbitrary.

Next, a fifth modification of the present embodiment will be described with reference to FIG. In this modification, the slit-shaped oil retention hole 30 in the first modification is divided into two in the circumferential direction, and the axial outer ends of the two oil retention holes 30 are connected in the circumferential direction. Then, this connected portion becomes an oil storage unit 32 for storing lubricating oil. According to this modification, the strength of the cage 14 can be increased, and the amount of lubricating oil stored in the oil retention hole 30 can be increased. The number of divisions of the oil retention holes 30 is arbitrary. The cross-sectional shape including the oil retention hole 30 and the oil storage portion 32 is the same as that of the oil retention hole 20 shown in FIG.

The present invention is not limited to those exemplified in the above embodiments, and can be appropriately modified without departing from the gist of the present invention.

10 Tapered roller bearing 11 Outer ring 11a Outer ring raceway surface 12 Inner ring 12a Inner ring raceway surface 13 Tapered roller 13a Rolling surface 13b Large diameter side end surface 13c Small diameter side end surface 13d Recess 13e Circular contact surface 14 Cage 15 Large diameter side annular part 15a Axial inner end surface (pocket surface)
16 Small diameter side annulus 16a Axial inner end surface 17 Pillar 18 Pocket 20 Oil retention hole (circular shape)
21 The outermost surface of the oil retention hole 22 The innermost surface of the oil retention hole 30 Oil retention hole (slit shape)
30a Groove end 31 End connection side CL Bearing central axis W Residual width of oil retention hole W1 Radial width of axial outer end of oil retention hole W2 Radial width of axial inner end of oil retention hole

Claims (6)

An outer ring having an outer ring raceway surface on an inner peripheral surface, an inner ring having an inner ring raceway surface on an outer peripheral surface, a plurality of tapered rollers provided to be rollable between the outer ring raceway surface and the inner ring raceway surface, and the plurality of tapered rollers. It is equipped with a cage that holds the tapered rollers at approximately equal intervals in the circumferential direction.
The cage has a large diameter side annular portion, a small diameter side annular portion coaxially arranged with the large diameter side annular portion, and the large diameter side annular portion and the small diameter side annular portion as axes. A cone having a plurality of pillars connected in the direction and provided at substantially equal intervals in the circumferential direction, and a pocket formed between the pillars adjacent to each other in the circumferential direction and holding the tapered rollers so as to be rollable. Roller bearings
At least one oil-retaining hole for holding the lubricating oil by capillary force is formed in the large-diameter annulus portion so as to penetrate the large-diameter annulus portion in the axial direction.
The radial width of the oil retention hole is set to be 0.5 mm or less and gradually becomes smaller from the outer side in the axial direction to the inner side in the axial direction.
A tapered roller bearing characterized in that the outermost surface of the oil retention hole is formed substantially parallel to the bearing central axis. The tapered roller bearing according to claim 1, wherein the surface on the innermost inner diameter side of the oil retention hole is formed so as to gradually incline outward in the radial direction toward the inner side in the axial direction. The tapered roller bearing according to claim 1 or 2, wherein the oil retaining hole has a circular shape or a slit shape along the circumferential direction of the large diameter side annular portion. The large-diameter end face of the tapered roller is provided around the circular recess formed in the center of the large-diameter end face and the concave, and is in contact with the axial inner end surface of the large-diameter ring portion. With a possible annular contact surface,
The opening on the tapered roller side of the oil retention hole is provided so that the contact surface of the annular contact surface and the axial inner end surface of the large diameter side annular portion are contained in a region where the tapered roller is overlapped in the longitudinal direction. The tapered roller bearing according to any one of claims 1 to 3. The tapered roller bearing according to any one of claims 1 to 4, wherein the inner end surface of the large-diameter annular portion in the axial direction is formed in a concave spherical shape. The tapered roller according to any one of claims 1 to 5, wherein the lubricating oil is intermittently supplied to the inside of the bearing, or the lubricating oil inside the bearing is used in a lubricating environment in a small amount. Roller bearing.

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